Single-tip Scanning Probe Microscopes (SPM), such as the Scanning Tunneling Microscope (STM) and Atomic Force Microscope (AFM), are critical tools for the investigation of structural and electronic properties of thin film materials and devices. For example, these single-tip SPMs form one or more images of a thin film material or device using a physical probe that scans the target.
However, single-tip SPMs are limited to static measurements such as the local density of states and near-sample surface effects. As a result, a range of fundamental phenomena that exist in thin film materials and devices are inaccessible. As just one example, the effects of dislocations and grain boundaries in thin films cannot be characterized, as the ability to perform trans-conductance (conduction between two tips) measurements at the nanoscale is a critical gap. Trans-conductance would enable a richer understanding of how electrons transport and interact with their surroundings by offering insight into the local density of states, tip-sample coupling, transport mechanisms, scattering phase shifts and inelastic free mean paths of electrons.
Multiple-tips SPMs have been proposed as a way of overcoming the inherent limitations of the single-tip SPM. However, there have been significant challenges to engineering a suitable multiple-tips SPM. Previous approaches to a multiple-tips SPM have relied on independent macroscopically-fabricated probes. These platforms are complex, difficult to actuate, and have limited scale-down. They are also prohibitively expensive to manufacture.
Accordingly, there is a continued need in the art for multiple-tips SPMs that are both cost-effective and easily manufactured and functionalized to the specific investigation for which they will be utilized.